miR-125a-5p expression is associated with the age of breast cancer patients.

Dysregulated miR-125 observed in multiple cancer types has suggested that it is involved in malignant proliferation and invasion. However, the clinical significance of miR-125 in human breast cancer (BC) has not yet been fully elucidated. In the present study, the expression of miR-125a-5p/3p and miR-125b in 143 pairs of BC and normal adjacent tissues (NATs) was measured by real-time quantitative PCR, and the correlation between expression and clinicopathological features was explored. miR-125a-5p and miR-125b were significantly down-regulated in BC tissue samples compared with their matched NAT samples, while the difference in miR-125a-3p expression between BC tissues and NATs was not statistically significant. The expression level of miR-125a-5p was found to be significantly higher in younger patients (<35 years) than in older patients (≥35, P = 0.005). When the patients were divided into three groups according to age (<35, 36-48, and ≥48 years), a gradual reduction in miR-125a-5p expression was observed in BC tissue samples that correlated to increases in age (P = 0.009). There were no significant correlations between miR-125 expression and other clinicopathological features including tumor size, histological grade, hormone receptor status, Her-2 status, and lymph node metastasis. Taken together, these findings suggest that miR-125a-5p may play an important role in BC progression in an age-dependent manner, and that the down-regulation of miR-125a-5p and miR-125b may serve as independent predictors for breast cancer.